Concentrator



May zo, 1924. l 1,494,480

F. E. HAWKESWORTH CONCENTRATOR Filed June 6. ZIlv 2 Sheets-Sheet 1 Maf," E@ 7 392% F. E. HAWKESWORTH CONCENTRATOR 5. i921 2 Sheets5heet 2 Jun-e Filed Patented May 2Q, 1924s FRANK E. nawxnswon'rn, or monteren, NEVADA.

CONCENTRATOR.

Application led June 6,

T0 all whom t may concern:

Be it known that I, FRANK E. HAWKES- WORTH, a citizen of the United States, residing at Tonopah, `in the county of Nye and State of Nevada, have invented a new and useful Concentrator, of which the following is a specification.

My invention relates to the art of saving values from mineral bearing substances, being more particularly a dry concentrator. in some forms of concentrators now in use it is customary to use a fixed riffie on the surface of the concentrator in which case the concentrator so constructed must be stopped at intervals in its operation for the purpose of removing the values `from the rifles, consequently considerable time is lost. One of the principal objects of my invention is to produce a table having rifiies thereon of simple form and construction which continuously during` the operation deliver the values caught by the riffles to a conveyor or receptacle used for that purpose. v

Another object of my invention is to produce a concentrator of the class described of simple form and construction in whichk the agitation of the table surface is yproduced by the alternate application of pressure and vacuum to the same. Other objects and advantages will appear hereinafter from the following description.y

Referring to the drawings which arefor` illustrative purposes only:

Fig. 1 is a side elevation partly in section of a concentrator embodying my invention.

Fig. 2 is an enlarged sectional view of a f portion of the table shownin Fig'. 1-1.

Fig. 3 is a vertical sectionalview looking from the rear ofthe machine shown in Fig. 1, such sectional view'lbeing taken through the air and vacuum valves. i

Fig. 4 is an enlarged sectional view on line 4,4 of'Fig. 2, a portion of the samek being broken away to better illustrate thev construction.

Fig. 5 is an enlarged sectional viewof the screen construction. y y

The apparatus consistsof a supporting Aframe having uprights 11, 12 and 13 andy timbers 14. Supported between the up-` rights 11 and 12 is the table `generally inf` dicated at 15, which table consists of side members 16 and 17the side member 16 being deeper than the side member 17 and the i921.k serial No. 475,396;

two members being connected at the bottoni to an inclined iioorl.

20 designates an apron which delivers the material to be `worked from a hopper 21 to the surface of the concentrator table, this surface consisting of a series of screens 22 having interposed therebetween riffles 23, T he material passing over the lastv riile `23 is discharged overL a plate 24 which forms :t continuation of the table.- Each riffle 23 `consists of a narrow casing which extends transversely across the table,'made of sheet metal and` consistingof an inlet portion 25 and an outlet portion 26, the inlet portion 25 discharging into a feed chamber 27 rand the feed chamber 27 discharging into the outlet portion 26 which is at the opposite side of the feed chamber to the inlet portion.- The casing of `which the riffie is formed is preferably made of two plates 30 f and 31 braced or held apart at intervals by means' of spacers 32, the plate 30 being formed with a curvedy portionor pocket33 which,together with the off set portions 34 j of the plate 31, formthe feed chamber `27.

`The plates 30 and 31 are secured in any suitable manner to end plates 35 preferably `formed of castmetal in which are sup ported bearings 36 `of a shaft or spindle 37. The'shaft 37 extends longitudinally through thechamber 27 and is provided with wings or paddles 38 secured thereto in any suitable lnanner.

The lowermostr-iiiie 23` is placed against` the endwall 40 `of ythe table, and the other zriiiies are placedagainst cross-bars 41, the

riflies being supported in the table by the hub 42 of the vbearings 36 which extend throughzthe side walls 16 and 17 of the table. 4The shafts 37 extend through the side walls "of thetable at one side thereof yand are each provided with aworrnwheel 4-4 engaged by wormsl45 ona shaft 46, the shaft 46 being driven from aworm 47 on a shaft-48 through the medium of a worm Wheel 49 secured to the shaft 46. y f The shaft 48 is driven through gears 50 and 51 from a shaft 52 which in turn is driven from a shaft k53 by a worm 54 thereon engaging with a worm wheel 55 on the shaft 52. The shaft 53 is provided with a pulley 56 driven by a belt 57 from a pulley 58 on ashaft 59,.the shaft 59 being mounted in, suitable bearings y60 supported on ythe frame of the Vapparatus and driven by means of a pulley 61 from any suitable source of power.

Arranged between each rilile 23 are the screens 22 consisting of a frame 65 over which is secured the screen body 66. This consists of a sheet of fine wire mesh 67 of about one-eighth (t) of an inch drawn over the frame as tight as possible and tacked fast to the under side of the frame. Over this is placed one thickness of burlap 68 likewise drawn tight and tacked fast, and over the burlap is placed, in the same manner, two or three thicknesses of medium weight muslin indicated at 69 and over this a sheet of very light wire mesh indicated at 70, which is primarily Vfor'the purpose of protecting the surface ofthe muslin from wear of the 'material `passing thereover. The wire screen 67 is primarily for the'purpose of giving the screen fthe 'necessary strength and the burlap .and muslin are for providing a sufficient resistancetothe pas* fsageof air therethrough ashereinafter referred tol and for the'purpose `of carrying the material being 'concentrated 'over the table.

After the layersof the different materials are placed over the frame, as hereinabove referred to, the layers may be stitched together as indicated at 71. The screens when so made up are placed in the table, one side or edge of the screen'frame resting on the body of a rilfle as shownin Fig. 2, the opposite side resting on the cross-bars 41 and the twoends upon cleats 72 secured to the inner side of the table. irlhe screens 22 are'firmly held ins'uch position by means of strips 7 4 which extend along the table above the screens, beingsecured' to: the sides 16 and 17 of the table by'woodnscrews indicated at 75. l'The screens arevfurther'held' firmly in place by means of rods 76which engage eyes 77 secured to crosspiecesf78 `on the screen frames, the rod 76 extending through the floor 18 of the table land nuts 79 being provided to-secure the rods inf the floor of the table. y

t is to be noted that the cross pieces 7 8 in the screen frames'are considerably below the screen surface and the sides `ofthe'frame are beveled as indicatedat'SO so'that'the same present a very small edge to the screen surfacer thereby #allowing the'V full' extent of Vthe exposed screenlsurface to'i be agitated in the manner hereinafter' l described. p

Leading rinto theE table,\vunder ithescreens 22 "therein, isfan'v air pzrssage82- which connects 'with Apipes83 'and' 84,* the communication between the'pipe83 and the air'passage 82 being controlled by thevalve'B'and' the The valve membersi87 ande88 in lthe by means of rods 89 and 90 respectively to eccentrics 91 and 92 yrespectively on the shaft 59, such eccentrics being timed so that when one valve member is in raised or open position the other valve member is in lowered or closed position.

The pipe 83 is connected to a suitable source of constant supply of air under pressure, such as supplied by an ordinary low pressure blower of the rotary type (not shown). The pipe 841- is connected to any suitable apparatus (not shown) for producing a partial vacuum in the pipe 84.

The apparatus is operated in the following manner:

The material to be worked is fed from the hopper 21 to the apron 20, then to the table surface comprising the screens 22, which surface ispractically continuous except for the rifiies which extend across the table betweenthe screens. The plate 30 of each riflle extends above the surface of the table as indicated at 95, whereas the upper edge of the plate 31 is substantially level with the screen surface.

The'angle of inclination of the table is approximately twenty-one (21) degrees, which is not suflicient to cause the material to slide down and over the table. The pas sage of material over the table is caused by repeated alternate impulses of air pressure '7 and the application of vacuum to the screens.

WV hen working what is commonly known as placer material, these impulses are made to occur at the approximate rate of about one hundred and vfifty per minute and the pressure placed upon the screen is just suicient to cause the screen to bulge slightly upwardly.A This impulse is caused by the ad .mission ofair under pressure from the pipe momentarily in suspense.

During thefirst or upward impulse,.the air pressure causes a'portion of the air to ,pass through the screens and through the material passing thereover. .This causes the .lightenmaterial in they mass to Afly upward and allows the heavier particles tobe .gravicaused by the vacuum ldraws the screen body down slightly faster than the wholewould come byy gravitation and theI tensionon the screen body andr at the same time drawing thescreen body below the tension line there- `fbygiving the screen bodyor surface more action. The limit of this kaction or movement; of the screen` body. up. and downy K and the rapidity of the impulses is regulated so llt) the edge 95 of the riliies and collected over the open top of the riflies through which they gravitate to the feed chamber 27 where the flow or passage of the concentrates through the rifl'les is more or less retarded,

being regulated by the operation of the shaft 37, the blades thereon removing the concen` trates from the feed chamber to the portion 26 or discharge part of the riiiies from which they are discharged. t

In the form of table shown in Fig. l, 100 designates a trough which is provided with a partition 101, the first two rilies of the table discharging in front of the partition into the trough 100 from which they are discharged through 'an outlet opening 102 into any suitable receptacle, the balance of the riflies discharging into the lower portion of the 4trough from whence they are also delivered to any suitable receptacle.

It is understood that the concentrates caught by the irst two riiiies on the table are of richer value than those caufrht in the succeeding rifles on the table and for this reason the concentrates from the first two rililes are preferably separated from the balance of the concentrates. The lighter 1 material on the table passes downwardly over the riiies and the tailings are dis-v charged over the plate 24: to any suitable conveyor or receptacle.

I claim as my invention:

y 1. A concentrator comprising: an inclined iexible screen; a plurality of hollow riffles spaced lengthwise of said screen and extending therethrough; means whereby air under pressure may be forced upwardly through said screen; and means whereby said screen may be subjected to the downward action of a Vacuum.

2. A concentrator comprising: an inclined flexible screen; a plurality of hollow riiiies spaced lengthwise of said screen and extending therethrough; retarding means in each of said riiiles; means whereby air under pressure maybe forced upwardly through said screen; and means whereby said screen may be subjected to the downward action of a vacuum.

3. A concentrator including: an inclined ieXible screen; a plurality of hollow riiiles spaced lengthwise of said screen'and extending therethrough; an air duct communieating with the under side of said screen; a vacuum duct communicating with the under side of said screen; a valve controlling said air duct; a valve controlling said vacuum duct; and means for alternately opening y and closing said valves.

In testimony whereof, I have hereunto set my hand at Tonopah, Nevada, this 9th day of May, 1921.

FRANK E. I-IAW'KESWORTH. 

